Light sensitive photographic color element



United States Patent 3,173,286 LIGHT SENSITIVE PHQTOGRAPHIC CQLOR ELEMENT Jozef Frans Willems and Willem Karel Koerber, Wilrijk- Antwerp, and Frans Clement Heugehaert, Kontich- Antwerp, Belgium, assignors to Gevaert Photo-Producten N.V., Mortsel, Belgium, a Belgian company No Drawing. Filed Nov. 7, 1960, Ser. No. 67,484 Claims priority, application Beigium, Nov. 5, 1959, 39,388, Patent 584,330 1 Claim. (Cl. 96-74) This invention relates to a process for improving the color reproduction of a color photographic multilayer material.

A diagrammatic representation of an element according to the present invention is as follows:

Silver halide layer sensitive to one color Colloid seperation layer containing orthodiamino compound having on one nitrogen a higher alkyl ballast group Silver halide layer sensitive to another color Film base When preparing photographic color images by color development of exposed silver halide layers, a silver salt image and a color image are formed, the latter being formed by the reaction of the oxidation products of the color developing substances such as the usual pdialkyl phenylene diamines with a color coupler present in said silver halide layer to form a dye.

In the color development of a color photographic material which is composed of dilferent layers, and which comprises three silver halide layers sensitized for the blue, green and red regions respectively of the spectrum, and which also contain a color coupler forming a yellow, a magenta and a cyan dye, respectively with the oxidation products of the developer, it is of paramount importance that the oxidation products of the developer, which are formed in a defined layer by the reduction of the exposed silver halide in said layer, couples in situ with the color coupler present therein.

Although in most cases the greater part of the formed oxidation products couples in situ, a rather important part of these products diifuses to an adjacent layer to couple with another color coupler present therein, resulting into an undesirable color whereby a bad color reproduction is obtained.

It is already known that some products belonging to the type of the cyclic compounds containing OH groups (US. Patents 2,360,290 and 2,401,713) comprising especially the hydroquinone derivatives (Belgian Patent 447,239, U.S.P. 2,336,327, Belgian Patent 453,723, U.S.P. 2,403,- 721, 2,675,314, 2,701,197, 2,704,713, 2,710,801, 2,735,- 765, 2,728,659, 2,732,300) and ascorbic acid derivatives (U.S.P. 2,336,327 and 2,728,611) and further hydrazine compounds (German Patent D.B.P. 984,810), which are capable of reacting with the oxidation products of the color developer.

These reducing agents show the property of oxidizing more easily than the color developing substance itself without, however, coupling with the color couplers on ima e color development. When using these compounds in the color photographic emulsions it is possible to eliminate the general color fog formation which may arise during the color development (e.g., by aerial oxidation of the color developer or by oxidation of the color developer by the colloidal silver of the yellow filter layer, is present).

However, when these compounds are present in the emulsion layers they affect the dye formation between the formed oxidation products of the color developer and the color coupler present since a competition arises between the dye formation on the one hand and the reduction of the formed oxidation products on the other hand. Moreover, although the cyclic compounds containing OH groups are quite capable of reducing the diffusing oxidation products of the color developer, they form colored oxidation products whereby the fog of the finished color images is increased in too high an extent.

By making these compounds non-migratory and by incorporating them into a layer between two differently sensitized silver halide emulsion layers or silver halide emulsion droplets, it would be possible to obtain a better color reproduction since said compounds catch the diffusing oxidation products and prevent them from forming an undesirable color in another layer, or in another emulsion droplet, as the case may be.

Moreover, the application of this technique shows the disadvantage of strongly increasing the color formation.

Furthermore, the reduction power of the ascorbic acid derivatives and of the hydrazine compounds is insufiicient so that the color reproduction is not satisfactorily improved when such compounds are used. It is also known that ascorbic acid and their derivatives decompose very rapidly and that their practical utility is but very limited.

Another technique for improving the color reproduction of color photographic images has been described in the Belgian Patent 560,907. According to this patent compounds are used which are capable to form colorless coupling products with the oxidation products of the color developer. For this purpose, compounds are com sidered having the structure of the usual ketone-methylene color couplers for yellow and for magenta, one hydrogen atom of the active methylene group of which having been replaced by an alkyl-, 2. cyclo-alkyl, an arylor an aralkyl group. These compounds form colorless products with the oxidation products of the color developer.

According to said technique, color photographic images with an improved color reproduction can be produced. During storage, however, these finished color images soon discolor which is probably due to the decomposition of the first formed leuco-derivative in the colored products. This discoloring is particularly Well noticeable at increased temperatures such as, e.g., on high-glossing the finished images.

Now it has surprisingly been found that a strongly improved color reproduction which does not have the abovementioned disadvantages can be obtained by adding to the layers, being present between two differently sensitized silver halide emulsions, ortho-diarnine compounds corresponding to the following general formula:

Patented Apr. 13, 1965 p a, 1 o a and A X K r ILNHR.

NH- O RzRa-R 4 wherein R represents a member selected from the group consisting of alkyl group, a substituted alkyl group, an aryl group, a substituted aryl group, an aralkyl group, a substituted aralkyl group, a sulfonyl alkyl-group, a substituted sulfonyl alkyl group, a sulfonyl aryl group, a substituted sulfonyl aryl group, a sulfonyl aralkyl group and a substituted sulfonyl aralkyl group;

A represents a member selected from the group consisting of a hydrogen atom, a halogen atom, a hydroxy group, an amino group, an alkyl group, an alkoxy group, an alkylamino group, a carboxyl group, a carboxylic acid alkali metal group, a sulfonic acid group and a sulfonic acid alkali metal group;

X represents a member selected from the group consisting of a hydrogen atom, a halogen atom, an alkyl group, a carboxyl group, a carboxylic acid alkali metal group, a sulfonic acid group and a sulfonic acid alkali metal group;

R and R each represent a member selected from the group consisting of a hydrogen atom, a methyl group and an ethyl group;

R represents a member selected from the group consisting of a carboxylic acid alkali metal salt group, a sulfonic acid alkali metal salt group and a hypo phosphorous acid alkali metal salt group; and at least one of the nitrogen atoms bearing a non-migratory making group.

The surprising character of the present invention is further supported by the fact that according to the published German patent application DAS 1,tl34,022, col. 1, lines 52-53, said products do not react with the color couplers present in the color developing bath.

The following examples of compounds correspond to the general formulae of the present invention, without limiting, however, the scope thereof.

(Compound 1 NH-C 171135 This compound can be prepared by the reduction of 2-nitro-4-sulfonic acid sodium salt-N-heptadecyl aniline.

(Comp ound 2) salt.

(Compound 3) This compound can be prepared by treating compound 2 with form-aldehyde and sodium bisulfite.

(Compound 4) I[Q'HC;5H33

This compound can be prepared by the reduction of' 4-(p-sulfo-phenylazo) -3-cetyl sulfonyl amino-N,N-diethyl: aniline and converting the latter into the hydrochloride.-

The azo dye is prepared by coupling the diazonium salt of sulfanilic acid with 3-cetyl sulfonyl amino-N,N-- diethyl aniline which has been prepared by the reaction of cetyl sulfochloride with N,N-diethyl-mcta-phenylene diamine.

(Compound 6) SO Na This compound is prepared by condensing compound 5 with benzaldehyde-o-sulfonic acid sodium salt.

(Compound 7) H5 C 3 C 2H5 This compound is prepared by reaction of Compound 5 with acetone and sodium hypophosphite.

All the above-mentioned compounds, dissolved in a suit-- able solvent, are mixed with a solution of gelatin or an other binding agent, appropriate for coating the inter-- layers previously described.

The concentration is chosen in such a way that the active compound concentration is defined between 0.025 g. to 2 g./sq. m. of interlayer but this concentration is not critical and its limits can be broadened if necessary.

These compounds are mixed with the aqueous colloid layers before the latter are coated. In case said compounds are not likely to be mixed with the colloid layers they are dispersed into same by means of an appropriate emulsifying agent. Very appropriate emulsifying agents are, i.a., alkyl benzene sulfonic acids having surfaceactive properties.

It is of common practice to apply in the color threelayer material, a yellow filter layer between the bluesensitive layer and the green-sensitive layer in order to eliminate the sensitivity to blue of the emulsion layers sensitive resp. to green and to red. Such a yellow filter layer is usually composed of colloidal silver. In this case the compounds according to the present invention can advantageously be used in the yellow filter layer since the colloidal silver exercises an oxidizing effect on the usual color developers whereby these oxidation products can diffuse to an adjacent emulsion layer to produce an undesirable color. If the compounds according to the present invention are used, these oxidation products are immediately reduced again whereby their noxious action is excluded.

The following examples illustrate the present invention without limiting, however, the scope thereof.

Example 1 A color photographic material, composed of an appropriate support, a silver halide layer sensitized for red and containing a color coupler for cyan, an interlayer cast from the following composition:

G. Compound 1 2 Gelatin 24 Water to 1 l.

G. p-Diethylaminoaniline sulfate 3 Sodium sulfite (anhydrous) 2 Sodium carbonate (anhydrous) 60 Potassium bromide 1.5

Water to 1000 cm.

The further finishing process is executed in the commonly known baths.

In this way a color image is obtained showing a much better color reproduction than the color reproduction of a color photographic material, similarly composed and finished but comprising interlayers which were coated from a pure gelatin solution.

This improved color reproduction can be measured, e.g., in the following way. The H- and D-curves of a green selection of a thin-layer material to be examined, are measured behind a green and a red filter in an Ansco densitometer. Then that step of the curves is selected the density of which behind the red filter is situated the nearest possible to 0.50; the unknown density is then measured behind a green filter on the same step.

Then is calculated which percentage of the unknown density represents the density of 0.50; the lower this percentage the better the color reproduction.

Thus, a side-absorption of 37% is noted for a color material composed according to the foregoing example and wherein the interlayers are cast only from a pure gelatin-solution whereas an improved side-absorption of 27% is noted for a material provided with inter-layers whereto the Compound 1 has been added.

Example 2 The same color photographic material according to Example 1, is used and also the same processing is followed, but instead of 2 g. of the Compound 1, now 1.5 g. of the Compound 2 is added to the gelatin interlayers. The obtained improved color reproduction is character- 6 ized by a much more improved and measured side-a sorption of 25%, in respect of a side-absorption of 37% of a similar material without addition of said compound to the interlayers.

Example 3 The same photographic color material according to Example 1 is used and also the same processing is followed but instead of 2 g. of the Compound 1, now 2 g. of the Compound 6 are added to the gelatin interlayers and to the yellow filter layer. The obtained improved color reproduction is characterized by a much more improved side-absorption of 25% which has been measured, in respect of a side-absorption of 37 of a similar material without addition of said compound to the interlayers.

We claim:

A color photographic multilayer film comprising a plurality of superposed diiferentially light-sensitive silver halide emulsion layers, each of said light-sensitive layers containing a color coupler for a primary subtractive color, and a colloid layer between at least two of said silver halide emulsion layers, said colloid layer being free of light-sensitive emulsion and containing an orthodiami-ne compound selected from the group consisting of compounds having the following general formulae:

X X I NHR1, NHR1 I'm i=ea and NHR1

I NHCRzRa-R4 wherein:

R represents a member selected from the group consisting of an alkyl group, a hydroxy-substituted alkyl group and a sulfonyl alkyl group;

A represents a member selected from the group consisting of a hydrogen atom, an alkyl group, an amino group and an alkyl amino group;

X represents a member selected from the group consisting of a hydrogen atom and a carboxylic acid alkali metal group;

R and R each represent a member selected from the group consisting of a hydrogen atom and a methyl p;

R represents a member selected from the group consisting of a sulfonic acid alkali metal salt group and a hypophosphorous acid alkali metal salt group, and

the alkyl group on at least one of the nitrogen atoms being a higher alkyl group which renders said orthodiamine non-migratory.

References Cited by the Examiner UNITED STATES PATENTS 2,522,802 9/50 Sargent et al. 96-100 2,575,027 11/51 Schmidt et al. 96100 2,733,143 1/56 Sprung 96-74 3,028,237 4/62 Loffier 969 FOREIGN PATENTS 558,258 12/43 Great Britain.

NORMAN G. TORCHIN, Primary Examiner.

PHILIP E. MANGAN, Examiner. 

